1. Field of the Invention
The present invention generally relates to a magnetic tape cartridge or tape cassette, and more particularly, to a tape cartridge having a pocket for tape loading at a front face of its main casing arranged to receive a head cylinder at the side of a video tape recorder in the pocket.
2. Discussion of Related Art
In a video tape recorder (VTR) such as a video camera or the like, there has been a demand for still a further compact size and a light weight VTR. In the above case, the tape cartridge to be dealt with has a pocket for tape loading at the front face of its main casing, and investigations have been made whereby a head cylinder at the side of a video tape recorder can be reduced in size for being accommodated in such a pocket, as a system which may meet the above requirements.
However, since there is a limitation to the size reduction of the head cylinder, the problem is related to the arrangement of the lid around the pocket of the main casing for inserting the head cylinder as far as possible without making contact.
FIGS. 38 and 39 show the construction of a conventional tape cartridge of this kind, more specifically, a tape cartridge for an 8 mm video tape. As shown in FIGS. 38 and 39, a front lid 11 for selective opening or closing of the front face of a main casing 1 is pivotally supported on the main casing 1, and at a position where a pocket 5 is formed, a back lid 130 is added to the front lid 11. By the above arrangement, in the lid closed state during non-use, the outer front face of the magnetic tape 3 is covered by the front lid 11 as shown in FIG. 38, while the rear face inner side of the tape 3 is covered by the back lid 130 thus, the magnetic tape 3 is surrounded by the front lid 11 and the back lid 130 including the upper face side of the pocket 5 for protection.
The back lid 130 is pivotally connected at its upper and lower intermediate portion, to the front lid 11 at opposite sides at points through shafts 131, and between the main casing 1 and the back lid 130, there is provided a guide means for opening the back lid 130 towards the upper face side of the pocket 5 for displacement. For the guide means, guide grooves 133 of a generally S-shape are formed on confronting faces of opposite side walls 6 at the left and right sides of the pocket 5, while armpieces 134 are provided to depend from opposite side edges of the back lid 130, with slider pieces 135 being laterally formed to extend from the forward ends of the arm pieces 134, so that the slider pieces 135 are received in the guide grooves 133 for sliding movement. In the above arrangement, by the guiding action between the guide grooves 133 and the slider pieces 135, the back lid 130 is also raised upwardly for opening, together with the front lid 11, as shown in FIG. 39.
However, as is clear from FIG. 39, in use in which the front lid 11 is opened, the lower edge of the back lid 130 is in a state where it is extended forward to a large extent onto the upper surface of the pocket 5. In other words, the effective opening height H of the pocket 5 is lowered by the presence of the back lid 130. Therefore, if it is intended to cause the head cylinder D to enter deep into the pocket 5, the head cylinder D undesirably contacts and is obstructed by the back lid 130, and this inconvenience has caused a bottleneck to achieve a compact size at the side of the video tape recorder.
Moreover, there is another conventional arrangement as disclosed in Japanese Patent Laid-Open Publication Tokkaisho No. 61-210584, in which in the back lid 130, as shown in FIGS. 38 and 39, the main portion 130a and upper lid portion 130b are separately formed, and the forward edge of the upper lid portion 130b is pivotally connected to the upper edge of the front wall 11a of the front lid 11, with the remaining construction being substantially the same as in the known construction of FIGS. 38 and 39. The upper lid portion 130b covers the open upper face of the pocket 5 during non-use, while, during the upward opening of the front lid 11, it rides over the upper face of the upper wall of the main casing 1 for retreating backwards. In the above arrangement, however, the main portion 130a also largely extends over the upper surface of the pocket 5, and the effective opening height H of the pocket 5 is still limited.